PIK3CA and lung adenocarcinoma: In this brief report, we describe the case of a Chinese male diagnosed with lung adenocarcinoma, harboring both a germline EGFR T790M mutation and concurrent somatic mutations in EGFR 19-Del, TP53, and PIK3CA. Following successful treatment with Osimertinib, he achieved a progression-free survival (PFS) of 19 months.